This invention relates to a board-to-board connector assembly for use in connecting two circuit boards and, particularly, to a connector and a mating connector which constitute the board-to-board connector assembly.
JP-A 2005-71769 discloses a board-to-board connector assembly comprising a plug connector and a receptacle connector, the contents of JP-A 2005-71769 being incorporated herein by reference. The plug connector is mounted on a first circuit board with its signal conductors such as terminals or contacts being soldered on a circuit pattern of the first circuit board so that the plug connector is fixed on the first circuit board. Likewise, the receptacle connector is mounted on a second circuit board with its signal conductors such as terminals or contacts being soldered on a circuit pattern of the second circuit board so that the receptacle connector is fixed on the second circuit board. Thus, all of the signal conductors of the disclosed board-to-board connector assembly are fixed to the first and the second circuit boards by using solder.
However, the solder makes it difficult to match impedance between the signal conductors and the circuit patterns of the first and the second circuit boards. The difficulty of the impedance-matching causes a problem on a high-speed signal transmission such as a differential transmission. Therefore, there is a need for a novel structure of a board-to-board connector assembly which allows easy impedance-matching between signal conductors and circuit patterns of circuit boards.